Electric machine and a turbo machine having the same

An electric machine, comprising:

• a stator;
• and
• a rotor disposed concentric to the stator, the rotor comprising at least one rotor module, wherein a rotor module of the at least one rotor module comprises:
• a rotor hub comprising:
• a hub body;
• and
• a plurality of elongate protrusions and a plurality of wedge protrusions located alternatingly on a periphery of the hub body and protruding radially from the hub body, each elongate protrusion of the plurality of elongate protrusions comprising an elongated portion and a head portion, wherein each wedge protrusion of the plurality of wedge protrusions has a trapezoidal-shaped profile, is unitarily formed with the hub body, and has a base portion and a top portion, wherein a width of the top portion is longer than a width of the base portion;
• a magnetic core comprising a plurality of core members disposed on the rotor hub, wherein the head portion of a first elongate protrusion of the plurality of elongate protrusions engages with a first core member of the plurality of core members, and wherein a first wedge protrusion of the plurality of wedge protrusions extends at least partially in a space between the first core member and a second, circumferentially adjacent, core member of the plurality of core members;
• and
• a plurality of permanent magnets, wherein a first permanent magnet of the plurality of permanent magnets is disposed in a space between the first core member and the second core member,
• wherein the rotor further comprises a non-magnetic insert disposed between the first core member and the second core member to retain the first permanent magnet in the space between the first core member and the second core member,
• wherein the first core member has a first side edge contacting the first permanent magnet and a second, opposite, side edge,
• wherein, along a radial direction of the electric machine, the first and second side edges converge towards one another until they reach an inflection point, and diverge from one another beyond the inflection point,
• wherein the space between the first core member and the second core member has a diamond-like shape,
• wherein the head portion of the first elongate protrusion is located radially inward of the inflection point,
• wherein the rotor further comprises a non-magnetic insert disposed between the first core member and the second core member to retain the first permanent magnet in the space between the first core member and the second core member,
• wherein the first core member has a first side edge contacting the first permanent magnet and a second, opposite, side edge,
• wherein, along a radial direction of the electric machine, the first and second side edges converge towards one another until they reach an inflection point, and diverge from one another beyond the inflection point,
• wherein the space between the first core member and the second core member has a diamond-like shape, and
• wherein the head portion of the first elongate protrusion is located radially inward of the inflection point.